I would steer away from stereotypical mean girl names. Maybe one, but don't have her be the "queen bee". The best way to think of it are who are the meanest girls in your school? I was born in the middle of the Jessica/Brittany phase, but the meanest girls in my school were Kyra, Kara, Gina and Miriam. A wide variety. So to make it more realistic chose a variety of names from different cultures. Mix some of the popular names the time they were born with some more unpopular names. I'd look at the Social Security list from the year these characters were born.